We evaluated the growth, neurodevelopmental status and speech and language abilities of 18 Stanford patients who received heart transplantation prior to their second birthdays. A second group of 15 children who required other heart surgery with cardiopulmonary bypass provided comparison. Age appropriate standardized tests were used. At the time of testing, patients ages ranged from 2.7 to 10.8 years and the time from surgery ranged from 4 days to 22 months. Transplant patients were shorter (p = .001) and tended to be lighter (p = .06) than comparison patients. They were also shorter (p = .0002) and lighter (.004) than the means for their ages. Neurologic abnormalities tended to be more frequent (5 vs. 1) in transplant and in comparison patients. Performance on the Bayley Scales of Infant Development-II (BSID-II) was approximately two standard deviations below the mean for transplant patients (n = 5. MDI = 71.2 +/- 20.3; PDI = 69 +/- 17.4) and within normal limits for comparison patients (n = 5). On the BSID-II, between group (transplant vs. comparison) differences approached statistical significance (MDI p = .06; PDI p = .07). Stanford Binet-IV (administered after 42 months) scores for both groups were within normal limits. On the Sequenced Inventory of Communication Development-Revised (SICD-R), younger (<42 months) transplant patients had greater dificulty with receptive and expressive language skills than comparison patients. The months below age level scores for receptive language approached statistical signicance for transplant (n = 5) vs. comparison patients (n = 4) (14.8 +/- 11.69 vs. 1.5 +/- 2.89; p = .06). Expressive language scores were not signficantly different for the two groups, but the trend was noteworthy (14.4 +/- 12.8 vs. 4.33 +/- 1.83; p = .14). In this study, younger transplant patients presented with growth difficulties, displayed worrisome developmental performance and tended to have receptive and expressive language difficulties.